The Study On Sedimentary Formation And Molar-tooth Carboantes In Mesoproterozoic, Yanqing-Huailai District

The thesis is part results of the marine Prospectivity project of Sinopec“The Research on Hydrocarbon of North China Platform and Two Rift Systems”and the Project National Science Foundation of China“The significant geologic event of Mesoproterozoic global change: Molar-tooth Carbonates′produce and die out”.The results come from detailed survey,descriptions and analysis on lots of outcrops and painstakingly work indoor, Based on the Theory and Methods about the principle of Astronomical System Sedimentary Geology and sequence stratigraphy, study the petrology, sedimentology, sequence stratigraphy feature of Yanqing-Huailai district,besides take Molar-tooth Carbonates as a priority research areas.Marine carbonates is the main deposition of Mesoproterozoic in Yanqing-Huailai district, followed by clastic rocks. The common rock types and the formation of the Environment carried out a detailed analysis, in particular the development of dolomite with chert bands as well as stromatolitic dolomite have been the focus of research.Author conside that dolomite with chert bands is Metasomatism of Silica in shallow water, stromatolitic dolomite is mainly formed In upper Subtidal zone to Upper inter-tidal belt depositional environment.Meter-scale cyclic of study area is divided into carbonate type, clastic rock type, carbonate rocks and clastic rocks interactive types.Among them, the type of carbonate meter-scale cycles are divided into L-M type, Subtidal type and Tidal flat ring types three types;meter-scale cycles- based on Clastic rock an be divided into tidal dynamic types and wave power types. Carbonate and clastic Interactive meter-scale cyclic types can be divided into carbonate– clastic types and clastic- carbonate rock types.Using of sequence stratigraphy and astronomical view of the deposition cycle theories of geology, Microfacies analysis, Meter-scale cyclic and Its Superposition, combining with Fisher diagrams, Divided Mesoproterozoic of Yanqing -Huailai district into 4 Megasequences, 16 super-sequences and 60 sequences.Gaoyuzhuang formation, Wumishan formation and Hongshuizhuang formation have been the focus study. Gaoyuzhuang formation is divided into 11 third-order sequences and grouped into 4 second-order sequences; Wumishan formation is divided into 30 third-order sequence and grouped into 4 second-order sequences; Hongshuizhuang formation is divided into a third-order sequence.Conducted a preliminary analysis Molar-tooth Carbonates of Chuanlinggou formation and Gaoyuzhuang formation inYanqing-Huailai district.Identifying six kinds of different shapes MT carbonates in the field, Studying shows that:MT carbonates are mainly distributed in shallow slope to the deep slope of Subtidal zone.establishment Sedimentary facies model and conducted a preliminary study of the causes of MT carbonates, Author consider that the formation and disappearance of MT carbonate is closely related to the chemistry changes of ancient ocean.